Contact assembly



y 29, 1952 w. J. ZENNER 2,605,366

CONTACT ASSEMBLY I Filed Jan. 13, 1949 -|NVENTOR WALTER J; ZENNER ATTORNEY iatentecl July 29, 1952 CONTACT ASSEMBLY Walter J. Zehner, Des Plaines, ill, assignor to Teletype Corporation, Chicago, 111.; corpora-- tion in? Delaware Application January 13, 1949, Serial No. 76,730

, Th present invention relates to electric switches, and more particularly to an improved type of electric switch for high speed operation.

The usual type of electric switch operates with a pivoted member being moved from engagement with one or the other of two contact points by some suitable operating means. Such a switch is satisfactory for many purposes, but when used as transmitting contacts in a telegraph system it does not operate satisfactorily, The main reason that the operation is not satisfactory for such use is that when the pivoted member is moved at high speed the contact made with its contact points will not be a good one, but bounce, arcing and vibration will occur, resulting in poor signals being transmitted over the telegraph system. Further, this causes pitting of the contact points in a short period of time, necessitating replacement thereof.

Accordingly, an object of the invention is to provide an electric switch which will operate satisfactorily at high speeds.

A second object of the invention is to provide an electric switch which when operated at high speeds will not bounce, are, or vibrate.

Another object of the present inventionis to provide an electric switch which will require a minimum of maintenance and replacement.

The primary cause for such bounce and vibration is because the movable member pivots about a point external from the contact points which it engages.

Thus, a still further object of the present invention is to provide an electric switch wherein the movable member does not pivot about an external point.

A still further object of the present invention is to provide an electric switch wherein the movable member pivots about the contact point with which it is placed in engagement.

' The electric switch comprises generally a movable member or contact carrier, which when moved to engagement with one or the other of two stationary contact points, will be fulcrumed about the stationary contact point of the contact pair to be closed.

A full understanding of the apparatus and its operation may be had by reference to the following detailed description, when read in conjunction with the accompanying drawings, wherein Fig. 1 is a front elevational view of one embodiment of the electric switch forming the inventicn;

1 Claim. 01-. zoo-6) Fig. 2 is a view, partly broken away, taken along the line 2- 2 of Fig. 1;

Fig. 3 is a front elevational view, partly broken away, showing a second embodiment or the invention; 7 I

Fig. 4, is a view taken along the line 4-4 of Fig. 3'; I

Fig. 5 is a front elevatiohalview of a third emse iment of the invention; and

' Fig. 6 is a side elevational View taken looking toward the left of Fig. 6.

Referring "now to Figs. 1 and 2, a first embodiment of the invention is illustrated and comprises a block H of non-conducting or insulating material which is formed'with a central bore I2 and two other bores, not illustrated, but through which pass conducting pins I3. The pins I3 are held in position by any suitable means, such as by the threaded members I4 at both the top and bottom of the block II. The upper por-' tion of theconducting pins I3 form stationary contact points.

Secured to the exterior of the block I I by any suitable means is a continuous strap I6 which is llormed with upturned edges H at two places thereof and is made of conducting material. A pair of contact points IB are secured by any suit able means, such as soldering, to the underside of the strap I6 in appropriate positions to overlie, but not engage, the contact points formed by the upper surface of the pins I3.

An insulating block I9 is secured to the mid section or the strap I6 with respect to the block II in such a manner that it overlies the central bore I2 and has its extremities extending within the channel or upturned edge sections I! of the strap I6. The block I9 is secured to the strap I6 by means of asuitable bolt 2I., to the lower eittrernlty or which is connected one end 'Of a spring 22, the opposite end of which is fastened by a pin 23 which extends across the lower surface of the block I I. The spring 22 is sufficiently strong to urge the contact points I8 toward their associated stationary contact points but engagement is not made because of the contour of the strap I6.

Secured to the block I9 is a lever 24 of insulat ing material, to which is pivotally connected the contact operatinglever 26, only a portion of which is shown. This latter lever 26 may be operated by any suitable means, depending on the use or the electric switch. One specific application '01 theinstant electric switch may be as the transmitting contacts of the telegraph keyboard transmitte'r illustrated and described in eopendin'gapplication Serial No. 95,964, filed on May 28, 1949, in the name of W. J. Zenner. In such use the lever 26 will correspond to the lever arm H2, shown in Fig. 2 of the noted application.

In Fig. 1 the switch is illustrated in a position with the left movable contact H3 in engagement with the stationary contact formed by the upper surface of the left-hand pin 13. If it be assumed that the members are being moved toward the illustratedposition, it may be seen that as the lever 26 urges the lever 24 toward the left the mentioned contact points will engage each other through the application of force by the block [9, with the spring 22 keeping them in engagement with each other. As the lever 24 moves further toward its maximum travel the pressure of the contact 18 at the fulcrum point, which is the engaged contact points, will be greater increasing the tendency for the two contact points to remain in engagement.

If the succeeding telegraph impulse is such that the right-hand contact points should be in engagement the arm 26 will be moved toward the right, Fig. 1, with the lever 24 being moved similarly. Under this condition the right-hand movable contact [6 will engage its stationary contact point formed of the upper surface of the right-hand pin [3. As the two contact points engage they will become the fulcrum point for the moving member with respect to the stationary member, the contact points remaining in engagement from the initial engagement thereof,

with no bounce or vibration occurring.

From the above description it may be seen that the present electric switch will operate to prevent any bounce, chattering, arcing, or vibration of the contact points once closed. This is true. not only for telegraph application, but for any use of the switch.

A second embodiment of the invention is illustrated in Figs. 3 and 4. As many of the elements of the latter disclosure are similar to those used in the first embodiment, similar identifying numerals will be used where possible, and similar elements and operations will not be described in detail.

The basic difference between the two embodiments is that the second one utilizes a domeshaped support 2! intermediate the strap [6 at the point of connection with the block [9 and the block II. The support 21 is formed with a circular opening 28 at the top thereof, through which the connecting pin 2| for the block l9, strap I6, and spring 22 extends. The support 21 is of sufficient height to prevent either of the contact pairs to be in engagement when the lever 24 is in a neutral position.

If it be assumed that the lever arm 26 is operated to move the lever 24 to make engagement of either of the contact pairs, the strap I6 and block 19 will ride over the curved upper surface of the support 21, but the fulcrum point for the members will still be at the closed contact pair. In this way there will still be no bounce, chattering or vibration at the closed contact pair.

' A third embodiment of the invention is shown in Figs. and 6, which, while formed of somewhat difierent mechanical elements, still utilizes the same principle of operation.

Referring now to these figures, it may be seen that an appropriate casing 3| is provided which houses a block 32 of insulating material having a central bore 33. The block 32 is also provided with two other bores through which pass and are secured two conducting pins 34, the upper surfaces of which form stationary contact points.

Extending through the central bore 33 of the block 32 is a T-shaped lever 36 which has an operating lever 31 mounted pivotally at the lower extremity thereof. A contact point 38 is secured to the underside near each extremity of the portion of the lever 36 forming the T, each of the contact points 38 being associated with one of the contact points formed by the upper surface of the pins 34.

A bracket 39 is secured to the casing 31 supporting a shaft 41 on which is mounted pivotally a U-shaped member 42 which is formed with an extending arm 43. The opposite extremity of the arm 43 is formed in a semi-circle and partially surrounds a pin 44 extending from the T- lever 36. A spring 46 is secured to the U- shapedmember 42 and extends to a pin 41 on the bracket 39. The spring 46 is so connected that the U-shaped member 42 and the arm 43 will be urged normally in a counterclockwise direction, Fig. 5, urging the contact points 38 toward their associated contact points formed by the upper surface of the pins 34. The pin 44 should preferably extend from a central point of the T-lever 36 in order that a balanced pressure may be exerted with respect to both of the contact points 38.

The embodiment of Fig. 5 is illustrated with both the contact pairs closed. However, in actual practice the operating lever 31 will normally be held in such a position that only one contact pair will be closed at one time.

The embodiment illustrated in Figs. 5 and 6 operates similarly to the other two embodiments. The spring 46 normally urges the arm 43 in a counterclockwise direction, tending to exert pressure to close the contact pairs. The operating lever 31 will be in one of its two positions, or moving from one to the other, which causes the T-lever 36 to be positioned in such a manner as to cause one of the contact points 38 to fulcrum about its associated contact point formed by the upper surface of the pin 34. As a change of selection is made in the operating lever 31 the T lever 36 will be moved from one position to the other, and as the lever 36 is not pivoted about an external point it will fulcrum about the contact pair which is desired to be closed. In this manner bounce and vibration will again be eliminated.

The spring 46 further performs the function of acting as a damper for the contact points and T- lever 36. Once the T-lever 36 has been moved and a contact pair closed, there may be some tendency for the contact pair to vibrate and be opened. However, for this to occur it is necessary that the spring 46 be extended, and as the bounce is normally not of suflicient energy to cause this it will not occur.

Further, it is desirable that the T portion of the T-lever 36 be constructed of a heavy mass. The purpose of such construction is that once the T-lever 35 is moved to one of its operated positions the heavy mass is more likely to cause the contact pairs to remain in a closed position than if a light mass element was used.

The T-lBver 38, Fig. 5, has been illustrated as being formed with its lower extremity in the shape of a pointer 48. This has been done in order to provide a rapid means of adjustment of the contact pairs, as at 38. The T-lever 36 may be operated normally to its two limits of movement, to the left and right, with the maximum points of the movement of the pointer 48 being noted. It will then be possible to position the pointer 48 at the midpoint of its maximum travels, with adjustments being made So that such would be a normal unoperated position. It is obvious from the above that any other desired setting of adjustment may also be made, if predicated on the movement of the pointer 48.

It should again be mentioned. that in all of the disclosed embodiments the movable member or contact lever is not pivoted about any permanent pivot point but instead the fulcrum point of its movement will be about the contact pair which is being closed at that time.

In the telegraph application of the present electric switch one of pins l3 or 34 will be connected to positive battery and the other pin 13 or 34 will be unconnected, with the signal output being taken from the strap 16 or the T-lever 35, depending on the embodiment utilized. If it is desired to use polar signaling the second pin I3 or 34 will be connected to negative battery. It is obvious, however, that electrical connections may be made to any suitable point depending on the use desired.

It may be further noted that as the actuating lever is operated to open one contact pair and close the other one there will be an interval in the travel that both of the contact pairs will be closed. However, this will not have any adverse effect on the use in the telegraph application. If such becomes undesirable for other uses the support 21 of Figs. 3 and 4 may be designed of a suitable height to prevent this from occurring.

While the instant invention has been described in specific embodiments and for utilization with particular apparatus, it is obvious that it could be incorporated in or with apparatus of other types where similar needs are present or desired, and further is not to be limited to the specific embodiments shown but for any embodiments within the scope and spirit of the invention.

What is claimed is:

In a high speed electric switch, in combination, a casing, bracket means secured to said casing, a pair 'of stationary contacts secured to said bracket means, an arm mounted pivotally to said bracket means, a T-lever mounted fioatably within said casing and engaged by said arm, a pair of contacts mounted on said T-lever for engagement with said stationary contacts, a tension spring connected between said bracket means and said arm for exerting a force on said arm in such a manner as to urge said T-lever contacts toward engagement with said stationary contacts, and operating means for said T-lever for imparting movement thereto for causing said T-lever to fulcrum about one or the other of said stationary contacts by engagement therewith of one said T-lever contacts, whereby a contact pair is closed, and bounce and vibration between said closed contact pair are eliminated, said operating means retaining said closed pair of contacts in such condition until operated subsequently to close the other pair of contacts.

WALTER J. ZENNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,736,746 McShane Nov. 19, 1929 2,182,977 Werner Dec. 12, 1939 FOREIGN PATENTS Number Country Date 613,418 Great Britain Nov. 29, 1948 

